Disk grinding machine



Sept. 10, 1935. F. M. HARGRAVE DISK GRINDING MACHINE 2 Sheets-smeet 1 Filed July 2. 1934 wuQ/Yvb Ffed lll. Hargrare Sept. 10, 1935. F M- HARGRAVE 2,014,327

DISK GRINDING MACHINE Filed July 2, 1954 2 Sheets-Sheet 2 Fred l-Hargrave Patented Sept. 10, 1935 UNITED STATES PATENT oFFlcE 2 Claims.

My present invention relates generally to grinding machines, and more particularly to machines for grinding and sharpening the concavoconvex disks such as are used in connection with harrows in heavy lduty Ifarm work as well as the scarifying, reworking and planing of oiled bitulithic and sheet asphalt roads and pavements.

It is the primary object of my invention to provide, in a manner as hereinafter set forth, a simple, effective rapid grinding and sharpening machine whichmay be operated continuously over considerable periods vwithout the necessity of replacement or truing .of the grinding wheel.

The fmeans by whichI accomplish the desired results, :as well 'as the further and more specific objects of my inventionand .the resulting advan- :tages thereof, will Vbe better understood and more :thoroughly appreciated from the following detailed description of my invention and its'various structural parts ,and operations, having reference `to the accompanying drawings, which form a part :of this specication, and in which,

Figure V1 .is a top plan View of my improved 'disk grindingmachine.

.Figure 2 is a side elevation thereof, certain parts being broken away and .in section.

Figure .3 is an enlarged vertical longitudinal -isection through the work holding and rotating parts.

Figure 4 is a similar view through the grinding wheel and its karbor holding arm.

Figure 5 is an enlarged end view ofthe arbor holding arm, and

Figure 6 is a diagram `showing the vmanner in which the grinding wheel is .applied to the disk.

Referring now tothese'gures, my invention is A'shown as mounted upon a stand or supporting frame I0, the only feature ofimportance of which as regards my invention being that itaifords `an rupper horizontal top piece II. r'I'hus the supporting legs I2 inclined from this top piece may -be varied as convenience suggests, so long as the 'stand as a Iwhole is efficiently anchored.

Across the top piece II, adjacent to one side thereof, is a Work shaft support consisting of an elongated casing I3 provided with outstanding ifeet I4rnear its ends connected by boltsor-suit- 'able anchoring members I5 to the stand. This :casing II3 rishollow throughout,with vopen ends into which are .tted nroller bearings I6 for vthe `spaced bearing portions lIl of the work shaft I3 .thusmounted to freely-rotate axially ofthe casing.

The rollerbearings IG-abut shoulders annularly ofthe shaft f I.8.between its bearing portions I 'I .clamping element 35. Aa ,fixed vertically -disposed ,forwardly opening yoke-shapedarm `36 at one end thereof. Averti- Vcal, pivot ;3'! issecured to armi36 forthefpurpose yof pivotallyconnecting the inner end of a horipositioning .frame v38 with thebracket `3,3. frame 38 is formedofA an outer and aninner yokeshaped partV ,38 ...3,8 `respectively which open in and its central enlarged portion I9 within the casing 4I 3, and are held against such abutments -by end plates 20 and 2| which `are secured to theforward and ,rear ends of the casing, as vlvyrmeans vof bolts, to `close said ends -Whereby the interior of 5 the casing may form an oil reservoir, Aoil being provided thereto through a side oil inlet klitting 22.

Outwardly beyond the end plates 2,0 and ,2l7 the work shaft I3 -has reduced forward and rear eX- 10 tensionsZS and 24, upon :thelatter o f .which `is secured a lpulley 25 which maybebeltconnected to any suitable source of power for rotating the Work shaft Vat high speed.

-On the yforward extension 2310i the shaft, the l5 Work, ka-disk 25, may be clampedibetween :inner and Vouter circular axially apertured clamping members .2l and 28, the disk being placed on the :shaft extension 23 with a bushing .29 around the `latter `,to interttheaxialopeningoithe disk-,and 20 insure its concentric vdisposition with respect to the lshaft I8. vObviously it will be necessary to provide bushings vof various .diameters for this purpose, and it is `equally plain the clamping members 2'! and 28 will -be formed on one face 25 With offset beveled marginal binding surfaces.

,The said surfaces extend in opposite .directions with respectto each other and are lindicated at 21', 28 to engage the concave vand convex faces .of thedisk 26, since it is desired to mount the 30 :latter-with its convex facepresented forwardly.

.To secure the work invplace as above, the shaft extension 23 is threaded at,its,forward.freeend -`for the reception of a clamping nut 3i) which' .ofthe top piecegI I of thestandl 0 is anadjustable ysupporting bracket33 formed with an elongated slot.,34l length-wise thereof. justablly connected to top/piece I Iby-a detachably 45 ,Thebracket y33 is ad- The bracket 33 includes 50 zontally disposed grinding wheel carrying and The an `outwardlylateral direction with .respect to 55 the length of said frame. The part 38 is of materially less width and depth than that of the part 38". The parts 38', 38" are flush at their open ends. The closed end of part 38" extends inwardly beyond the closed end of the part 38. The rear side of part 38 is formed by the arm 38 arranged within arm 38 and supported upon the bottom of the latter. The bolt 31 extends through a vertical opening in the arm 38"'. The forward side of part 38' is formed by an arm 39. The rear side of part 38 and the forward side of part 38 is formed by an arm 48. The arms 39 and 49 having aligning openings 39', 48 respectively. The opening 40' is of greater diameter than opening 39. The arrangement of the frame 38 in the manner as shown permits it to swing outwardly with its free end forwardly of the edge of the disk and with the pivot for its inner end positioned inwardly adjacent the disk.

The grinding wheel 4l, is held between clamping collars 42 and 43 on the forward reduced extension 44 of the grinding shaft 45, by means of a clamping nut 48. This shaft 45 is journalled axially of the tubular housing 41 at one end of the grinding wheel supporting arm 48, through roller bearings 49 within opposite ends of said housing. One end of the housing is closed by an end plate 59 bolted thereto and provided with an external annular groove 5l receiving a similar or companion rib 52 of the adjacent wheel clamping collar 42. The other end of the housing 41 is closed by the end cap 53 and thus the hollow interior thereof forms an oil reservoir to which oil may be supplied through an oiling plug 54.

The arm 48 has at its other end an axially bored cylindrical extension 55 in approximately the body plane of the grinding wheel 4I and projecting away therefrom at right angles to the housing 41 and the grinding wheel axis. This extension 55 is slidably disposed through the inner bearing extension 48 of the frame 38 previously mentioned and is keyed against rotation therein by a key 55 to lock the supporting arm at a rearward and downward angle as plainly seen in Figures 1 and 2.

Passing through the opening 39', in arm 39 and the bore 51 of extension 55 to the rear end of said bore 51 is a slide rod 58 having its forward portion peripherally threaded, as at 58. The rear'end of extension 55 is formed diametrically thereof with spaced apertures 59 which open into the bore 51. Extending through the apertures 59 and the rear end of rod 58 is a pin 68 for coupling the extension 55 with the rod 58 to provide for them to bodily shift in unison relative to arms 39 and 40. Encompassing the rod 58, forwardly of and abutting arm 39 is a revoluble handle member 6I. The latter is internally threaded for engagement with the threads 58' of rod 58. The member 6| functions to shift the rod 58 forwardly and rearwardly with respect to the arms 39, 40. Surrounding the rod 58 and interposed between arm 39 and extension 55 is a coiled cushioning spring 82 for the grinding wheel structure. The tension of spring 62 is increased or diminished on the adjusting of rod 58 by handle member 6l. The opening 39 of arm 39 is of greater diameter than and has its wall spaced from rod 58. The latter is held at all times concentrically with respect to the wall of opening 39 by the extension 55. The latter has a sliding t with the wall of opening 48 of arm 40. The spring 62 and a portion of the extension 55 is arranged within the yoke-shaped part 38 of the grinding wheel structure carrying and positioning frame 38. The major portion of the grinding wheel structure is arranged within the yokeshaped part 38" of the frame 38. The arms 39, 48 and 38 are termed respectively outer, intermediate and inner arms of frame 38. 5

It becomes apparent from the foregoing that after clamping the disk to be sharpened, as for instance disk 2S, upon the work holding shaft in the manner previously described, so that it is truly concentric with the shaft, the disk is rotated at lo high speed, whereupon the operator grasps handle 6 l, having previously rotated this handle to' place spring 62 under the desired tension, and swings the grinding wheel holding frame 33 horizontally and forwardly on its pivot 31 until the peripheral 15 face of the grinding wheel 4| comes into engagement with the disk at the convex side of its edge. When thus engaged with the work, it will be noted from the dotted line position of the parts in Figure l, the axis of the grinding wheel 4l is at an 20 angle to the axis of the work holding shaft, and consequently the disk 23, of approximately 45 degrees, and its body plane will also approximate that degree of angularity with respect to the engaged portion of the work edge, as seen by refer- 25 ence to Figure 6, and by reason of the previously 4described inclination of the supporting arm 48 and the wheel shaft 45. It is obvious then that in the rotation of the disk, its material on the convex side of its edge will sweep angularly across 30 the peripheral face of the grinding wheel from one side to the other and the wheel will be gradually and uniformly rotated on its own axis so that in the grinding operation it will be worn down evenly and without the necessity of more or less 35 frequent refacing operations.

The operator controls to a considerable extent the pressure of the grinding wheel against the work, but this pressure is relieved in some measure by the spring 52 which permits the grinding 40 wheel to yield wherever inequalities of either the wheel or the work are present and wherever, for any other reason, binding is threatened.

My improved grinding and sharpening mechanism solves the problem of properly sharpening 45 the modern alloy steel disks used in heavy duty, as far as general or casual use is concerned, and results in the removal of the material back of the cutting edge of the disk in such manner as to bring about a sharp cutting edge with maximum material reenforcement of said cutting edge in much the same degree as the disk comes from the factory in the first instance.

No grinding is done on the concave side of the cutting edge, though in some instances it is necessary to remove the burr, if such develops, from the grinding of the convex side. For this purpose I may utilize a burr removing grinding wheel 83 shown only in Figure 2, mounted to rotate in connection with a lever 64 having a handle 55 on one 60 end, and having a pivot opening at its other end by which it may be applied, when used, upon the upper end portion of the pivot bolt 31. Thus the wheel 53 may be shifted against the concave side of the cutting edge of the disc without difficulty, 65 and may, like the grinding wheel 4|, be set with its body at such angle between the plane of the disk and the plane of the axis of the disk, so as to bring about a cutting action across the entire peripheral face of the wheel and a uniform rotation thereof, minimizing and equalizing wear of the wheel with a constant truing of its grinding surface.

Furthermore, while not in any manner essential to my invention, the safety of the operator may be preserved during use of the grinding mechanism by any suitable guards, both for the rotating disk 26 and the grinding wheel 4I, as I have indicated in a general way at 66 in Figure 2 and 61 in Figure 4.

What I claim is:-

1. In a disk grinding machine, a vertical support, a driven element carried by and extended at one end from said support, means for clamping the disk to' be ground to the extended end of said element, a manually bodily shiftable swingingly mounted elongated horizontally disposed grinding wheel structure carrying and positioning frame, means for pivotally connecting the inner end of said frame to said support inwardly adjacent to the extended end 0i said element, a grinding wheel structure arranged within and depending from the frame an-d formed with a laterally extended part having the outer portion thereof slidably mounted in the body of said frame intermediate the ends of the latter for disposing said structure in depending relation and at an outward inclination, from its bottom to its top with respect to the frame, a cushioning means for said structure positioned within the frame forwardly of said portion, an-d an adjustablemeans carried by and lengthwise of the frame, permanently extending beyond the outer end of the frame, supporting said cushioning means and connected to said portion for selectively shifting said structure bodily in opposite directions with respect to the frame for varying the tension of said cushioning means.

2. In a disk grinding machine, a Work holder, a bodily shiftable support pivoted at its inner end with and shiftable towards and from said work holder, a tubular housing open at each end, an

imperforate closure for one end of the housing, 10

an axially apertured closure for the other end of the housing, bearing means within the housing at each end thereof and spaced from said closures, a shaft extending through said bearings and apertured closure and projecting outwardly from the latter, a grinding wheel mounted on the projecting end of said shaft, means for clamping the Wheel to the projecting end of said shaft, said means revolving in said apertured closure, and a supporting arm for, integral with and disposed at an angle to the housing and being formed at its outer end with a tubular extension disposed at right angles thereto, said extension being mounted in said support outwardly adjacent the pivoted end of the latter to provide for the housing being 25 bodily carried by and suspended from the support.

FRED M. HARGRAVE. 

